CN105874566B - The manufacturing method of manufacturing silicon carbide semiconductor device - Google Patents
The manufacturing method of manufacturing silicon carbide semiconductor device Download PDFInfo
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- CN105874566B CN105874566B CN201580003475.9A CN201580003475A CN105874566B CN 105874566 B CN105874566 B CN 105874566B CN 201580003475 A CN201580003475 A CN 201580003475A CN 105874566 B CN105874566 B CN 105874566B
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- 239000004065 semiconductor Substances 0.000 title claims abstract description 141
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 title claims abstract description 137
- 229910010271 silicon carbide Inorganic materials 0.000 title claims abstract description 136
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 92
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims abstract description 58
- 238000010438 heat treatment Methods 0.000 claims abstract description 34
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical group [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 28
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 28
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 23
- 229910021334 nickel silicide Inorganic materials 0.000 claims abstract description 21
- RUFLMLWJRZAWLJ-UHFFFAOYSA-N nickel silicide Chemical compound [Ni]=[Si]=[Ni] RUFLMLWJRZAWLJ-UHFFFAOYSA-N 0.000 claims abstract description 21
- 230000015572 biosynthetic process Effects 0.000 claims abstract description 20
- 238000006243 chemical reaction Methods 0.000 claims abstract description 11
- 229910052799 carbon Inorganic materials 0.000 claims description 45
- 150000001721 carbon Chemical group 0.000 claims description 39
- 238000000034 method Methods 0.000 claims description 30
- 125000004429 atom Chemical group 0.000 claims description 17
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 6
- 230000006978 adaptation Effects 0.000 abstract description 8
- PEUPIGGLJVUNEU-UHFFFAOYSA-N nickel silicon Chemical group [Si].[Ni] PEUPIGGLJVUNEU-UHFFFAOYSA-N 0.000 abstract description 6
- 239000010703 silicon Substances 0.000 abstract description 6
- 239000004411 aluminium Substances 0.000 description 9
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 9
- 229910052782 aluminium Inorganic materials 0.000 description 9
- 239000007787 solid Substances 0.000 description 8
- 229910052751 metal Inorganic materials 0.000 description 6
- 239000002184 metal Substances 0.000 description 6
- 239000007790 solid phase Substances 0.000 description 6
- 238000004544 sputter deposition Methods 0.000 description 6
- 238000004833 X-ray photoelectron spectroscopy Methods 0.000 description 5
- 238000001556 precipitation Methods 0.000 description 5
- 239000000758 substrate Substances 0.000 description 5
- 239000007772 electrode material Substances 0.000 description 4
- 238000005477 sputtering target Methods 0.000 description 4
- 239000011248 coating agent Substances 0.000 description 3
- 238000000576 coating method Methods 0.000 description 3
- 238000009792 diffusion process Methods 0.000 description 3
- 230000005611 electricity Effects 0.000 description 3
- 239000011159 matrix material Substances 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000000921 elemental analysis Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000005669 field effect Effects 0.000 description 2
- 238000007429 general method Methods 0.000 description 2
- 229910044991 metal oxide Inorganic materials 0.000 description 2
- 150000004706 metal oxides Chemical class 0.000 description 2
- 239000010936 titanium Substances 0.000 description 2
- 229910003978 SiClx Inorganic materials 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- BVDKLOSQZNHXSI-UHFFFAOYSA-N [Si].[Ni].[C] Chemical compound [Si].[Ni].[C] BVDKLOSQZNHXSI-UHFFFAOYSA-N 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 239000002390 adhesive tape Substances 0.000 description 1
- AZDRQVAHHNSJOQ-UHFFFAOYSA-N alumane Chemical group [AlH3] AZDRQVAHHNSJOQ-UHFFFAOYSA-N 0.000 description 1
- 229910052786 argon Inorganic materials 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 235000013399 edible fruits Nutrition 0.000 description 1
- 239000004744 fabric Substances 0.000 description 1
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 230000008676 import Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 239000012071 phase Substances 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 238000004611 spectroscopical analysis Methods 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 239000010937 tungsten Substances 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
- H01L21/0445—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising crystalline silicon carbide
- H01L21/048—Making electrodes
- H01L21/0485—Ohmic electrodes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/02—Semiconductor bodies ; Multistep manufacturing processes therefor
- H01L29/12—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by the materials of which they are formed
- H01L29/16—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by the materials of which they are formed including, apart from doping materials or other impurities, only elements of Group IV of the Periodic System
- H01L29/1608—Silicon carbide
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
- H01L29/66007—Multistep manufacturing processes
- H01L29/66053—Multistep manufacturing processes of devices having a semiconductor body comprising crystalline silicon carbide
- H01L29/6606—Multistep manufacturing processes of devices having a semiconductor body comprising crystalline silicon carbide the devices being controllable only by variation of the electric current supplied or the electric potential applied, to one or more of the electrodes carrying the current to be rectified, amplified, oscillated or switched, e.g. two-terminal devices
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
- H01L29/86—Types of semiconductor device ; Multistep manufacturing processes therefor controllable only by variation of the electric current supplied, or only the electric potential applied, to one or more of the electrodes carrying the current to be rectified, amplified, oscillated or switched
- H01L29/861—Diodes
- H01L29/872—Schottky diodes
Abstract
Surface electrode film (4) are formed on the surface of manufacturing silicon carbide semiconductor portion (1), the second electrode film (3) that the surface electrode film (4) stacks gradually the first electrode film (2) being made of nickel and is made of nickel silicide (NiSi) forms.Later, by made using heat treatment manufacturing silicon carbide semiconductor portion (1) silicon atom and first electrode film (2) nickle atom reaction and make the almost all nickel silicide (Ni of first electrode film (2)2Si), to form the Ohmic contact between manufacturing silicon carbide semiconductor portion (1) and surface electrode film (4).Since second electrode film (3) contains silicon, so not reacted in heat treatment with the silicon atom of manufacturing silicon carbide semiconductor portion (1).First electrode film (2) with a thickness of 5nm or more and 10nm or less.Second electrode film (3) with a thickness of 80nm or more.It so, it is possible to ensure the adaptation between the electrode film of manufacturing silicon carbide semiconductor portion (1) formation Ohmic contact and the wiring layer being layered on electrode film.
Description
Technical field
The present invention relates to the manufacturing methods of manufacturing silicon carbide semiconductor device.
Background technique
In the past, silicon carbide (hereinafter referred to as SiC) semiconductor was relatively stable in heat, chemistry, mechanical aspects, as light-emitting component
Or high-frequency element, power semiconductor device (power device), expectation are applied to various industrial fields.Especially with
High-withstand voltage MOSFET (the Metal Oxide Semiconductor Field Effect Transistor: absolutely of SiC semiconductor
Edge grid-type field effect transistor) compared with the high-withstand voltage MOSFET for having used silicon (Si) semiconductor, with low excellent of conducting resistance
Point.In addition, the Schottky diode using SiC semiconductor has been reported compared with the Schottky diode for using silicon semiconductor,
Forward voltage drop is lower.
The conducting resistance and switching speed of script power device there are trade-off relation (trade-off relationship),
But the power device of SiC semiconductor is used to be possible to realize low on-resistance and high-speed switch speed simultaneously.For making
For low on-resistance with the power device of SiC semiconductor, important reduced between electrode film and SiC semiconductor portion
The contact resistance of the Ohmic contact (electrical contacts) of formation.In addition, the high speed of the power device for having used SiC semiconductor is opened
It closes for speed, the contact resistance of Ohmic contact is also larger problem.As having used the power device of SiC semiconductor to exist
One problem of practical aspect can be enumerated practical low suitable for being used to form for each device architecture and production (manufacture) process
The technology of the Ohmic contact of resistance is clear not yet.
As the technology for the method for being widely used as being formed low-resistance Ohmic contact between N-shaped SiC semiconductor portion, mention
Go out at a high temperature of 800 DEG C~1200 DEG C of degree, to the ohm for being coated in electrode film in N-shaped SiC semiconductor portion and being formed
Electrode assembly carries out heat-treating methods (for example, referring to following Patent Documents 1 to 3).As electrode material, there is known nickel
(Ni), tungsten (W) and titanium (Ti) etc..For the Ohmic contact especially with nickel as electrode material, it can be obtained 10-6Ωcm2
The practical contact resistance value of unit, becomes extremely desirable Ohmic contact.
However, in the case where using nickel as electrode material, because of high-temperature heat treatment, nickel film and the reaction of SiC semiconductor portion,
Formation is mixed with conversion zone (such as nickel silicide (NiSi) film) of the nickel-silicon-carbon (C) as the electric conductivity of electrode film.At this point, from
The carbon atom in SiC semiconductor portion free (diffusion) is largely precipitated near the surface of electrode film, and electrode film surface is almost by by carbon
Carbon-coating made of atom is precipitated covers.Therefore, there are electrode film and the further example of wiring of the stacking (formation) on electrode film
If the adaptation of aluminium (Al) film (wiring layer) is deteriorated, the peeling-off hidden danger of wiring layer.
As a solution to the problem, it is described in following patent documents 1 and wiring layer is being layered in nickel silicide film
Before upper, heat treatment will be passed through in the carbon-coating that nickel silicide film surface is precipitated due to the generation of the nickel silicide film as electrode film
And it removes.The material ratio of components by adjusting electrode film is described in following patent documents 2,3, is forming electrode film and SiC half
When Ohmic contact between conductor portion, makes the carbon atom and the electrode film reaction that dissociate from SiC semiconductor and generate carbide, thus
Carbon atom is inhibited to be precipitated to electrode film surface.
Existing technical literature
Patent document
Patent document 1: Japanese Unexamined Patent Publication 2013-222823 bulletin
Patent document 2: International Publication No. 2011/115294
Patent document 3: Japanese Unexamined Patent Publication 2013-219150 bulletin
Summary of the invention
Technical problem
As described above, forming the nickel film as electrode material in SiC semiconductor portion, electrode is formed using high-temperature heat treatment
In the case where the Ohmic contact in film and SiC semiconductor portion, there is the carbon atom to dissociate from SiC semiconductor portion and analysed in electrode film surface
Out, the problem of aluminium film etc. being layered on electrode film is easily peeled off.
In order to solve above-mentioned the problems of the prior art, the purpose of the present invention is to provide can ensure and SiC semiconductor
Portion forms the electrode film of Ohmic contact and the manufacturing silicon carbide semiconductor dress for the adaptation being layered between the wiring layer on electrode film
The manufacturing method set.
Technical solution
It achieves the object of the present invention to solve the above-mentioned problems, the manufacturing method of manufacturing silicon carbide semiconductor device of the invention
It is the Europe between the surface electrode film on the surface to form the manufacturing silicon carbide semiconductor portion of N-shaped and be formed in above-mentioned manufacturing silicon carbide semiconductor portion
The manufacturing method of the manufacturing silicon carbide semiconductor device of nurse contact, has following feature.Firstly, the first formation process is carried out, upper
The surface for stating manufacturing silicon carbide semiconductor portion forms the first electrode film being made of nickel as above-mentioned surface electrode film.Next, carrying out
The second step forms the second electrode film being made of nickel silicide as above-mentioned surface electrode on the surface of above-mentioned first electrode film
Film.Next, heat treatment procedure is carried out, by the silicon atom and above-mentioned first for making above-mentioned manufacturing silicon carbide semiconductor portion using heat treatment
The nickle atom of electrode film reacts and makes above-mentioned first electrode film silication, forms above-mentioned manufacturing silicon carbide semiconductor portion and above-mentioned surface electrode
Ohmic contact between film.Also, in above-mentioned first formation process, above-mentioned first electrode film is formed as into scheduled thickness,
So that the first carbon atom becomes the few containing ratio that can imported into the inside of above-mentioned second electrode film, above-mentioned first carbon atom is
In above-mentioned heat treatment procedure, when making above-mentioned first electrode film silication, dissociates and be diffused into from above-mentioned manufacturing silicon carbide semiconductor portion
The carbon atom of above-mentioned surface electrode film side.
In addition, the manufacturing method of manufacturing silicon carbide semiconductor device of the invention is characterized in that, in above-mentioned invention, upper
It states in the second formation process, formation is able to suppress the upper of the inside that above-mentioned second electrode film is imported into above-mentioned heat treatment procedure
State the above-mentioned second electrode film for the thickness that the first carbon atom is precipitated to the surface of above-mentioned surface electrode film.
In addition, the manufacturing method of manufacturing silicon carbide semiconductor device of the invention is characterized in that, in above-mentioned invention, upper
State in the second formation process, be able to suppress reacted in above-mentioned heat treatment procedure with above-mentioned manufacturing silicon carbide semiconductor portion form come
Form above-mentioned second electrode film.
In addition, the manufacturing method of manufacturing silicon carbide semiconductor device of the invention is characterized in that, it is in above-mentioned invention, above-mentioned
Second electrode film is that the containing ratio of nickle atom is 60atm% and the containing ratio of silicon atom is containing ratio of the 40atm% to nickle atom
Containing ratio for 70atm% and silicon atom is the composition of the range between 30atm%.
In addition, the manufacturing method of manufacturing silicon carbide semiconductor device of the invention is characterized in that, in above-mentioned invention, upper
It states in the second formation process, to form substantially phase with the above-mentioned first electrode film that has carried out silication in above-mentioned heat treatment procedure
Deng composition form above-mentioned second electrode film.
In addition, the manufacturing method of manufacturing silicon carbide semiconductor device of the invention is characterized in that, it is in above-mentioned invention, above-mentioned
First electrode film with a thickness of 5nm or more and 10nm or less.
In addition, the manufacturing method of manufacturing silicon carbide semiconductor device of the invention is characterized in that, it is in above-mentioned invention, above-mentioned
Second electrode film with a thickness of 80nm or more.
According to above-mentioned invention, reacting due to silicon because with the silicon atom in manufacturing silicon carbide semiconductor portion for surface electrode film can be made
The region of change only becomes first electrode film, can reduce the extra carbon atom generated when heat treatment.In addition, can will be described more
Remaining carbon atom imports second electrode film.Therefore, it is suppressed that most surface from carbon atom to surface electrode film precipitation.
Invention effect
The manufacturing method of manufacturing silicon carbide semiconductor device according to the present invention rises when forming Ohmic contact using heat treatment
It is precipitated to carbon atom is able to suppress to electrode film surface, it is ensured that the effect with the adaptation being layered between the wiring layer on electrode film
Fruit.
Detailed description of the invention
Fig. 1 is the flow chart for indicating the summary of the manufacturing method of manufacturing silicon carbide semiconductor device of embodiment.
Fig. 2 is the cross-sectional view of the state in the manufacturing process for indicate the manufacturing silicon carbide semiconductor device of embodiment.
Fig. 3 is the performance plot for indicating the Elemental redistribution of the depth direction of surface electrode film of previous example 1.
Fig. 4 is the table for indicating the thickness (Ni film thickness) and the first electrode film after heat treatment of the first electrode film of embodiment 1
The chart of face composition.
Fig. 5 is the surface composition for indicating thickness (the NiSi film thickness) and second electrode film of the second electrode film of embodiment 2
Chart.
Fig. 6 is the performance plot for indicating the depth direction elemental analysis of surface electrode film of embodiment 2.
Symbol description
1:n type SiC semiconductor portion
2: first electrode film (nickel film)
3: second electrode film (nickel silicide (NiSi) film of second solid phase state)
Specific embodiment
Hereinafter, explaining the preferred reality of the manufacturing method of manufacturing silicon carbide semiconductor device of the invention in detail referring to attached drawing
Apply mode.In the present description and drawings, for layer or the region of n or p is marked, electronics or hole is respectively referred to and is carried to be most
Stream.In addition, marking in n or p+and-refer to and is comparably high impurity concentration and low miscellaneous with the layer or region for not marking them
Matter concentration.It should be noted that in the description of the following embodiments and the accompanying drawings, marking identical symbol to identical composition, saving
Slightly repeat description.
(embodiment)
For the manufacturing method of the manufacturing silicon carbide semiconductor device of embodiment, illustrate to be formed by silicon carbide (SiC) semiconductor
The method of the Ohmic contact of the semiconductor portion (SiC semiconductor portion) and surface electrode film of composition.Fig. 1 is the carbon for indicating embodiment
The flow chart of the summary of the manufacturing method of SiClx semiconductor device.Fig. 2 is the manufacturing silicon carbide semiconductor device for indicating embodiment
The cross-sectional view of state in manufacturing process.The state just formed after surface electrode film 4, surface electrode film 4 are shown in Fig. 2
It is made of stacking gradually first electrode film 2, second electrode film 3 in N-shaped SiC semiconductor portion 1.1, N-shaped SiC semiconductor portion
The n that such as refer to the N-shaped being made of N-shaped SiC semiconductor semiconductor substrate (hereinafter referred to as SiC substrate), is layered in SiC substrate
Type SiC semiconductor layer or be set to SiC substrate superficial layer the region N-shaped SiC.Surface electrode film 4 can be formed to have
The front electrode of the silicon carbide semiconductor device (manufacturing silicon carbide semiconductor device) in N-shaped SiC semiconductor portion 1, can also be formed as carrying on the back
Face electrode.
Firstly, forming scheduled component structure (device architecture) (step S1) using general method.That is, in step S1
In, make the silicon carbide semiconductor device (semiconductor chip) with N-shaped SiC semiconductor portion 1.Each constituting portion of component structure is
Refer to the semiconductor regions or semiconductor layer formed according to component structure.Component structure can be in N-shaped SiC semiconductor portion 1
Internal and surface is formed with the composition of each constituting portion, is also possible to as a constituting portion and including N-shaped SiC semiconductor portion 1
Composition.Specifically, each constituting portion of component structure refers to, such as constitute in production (manufacture) MOSFET as front
The p-type base area of mos gate (insulated gate being made of metal-oxide film-semiconductor) structure of component structure and/or n+Type source region,
And/or constitute the n of back elements structure+Type drain region etc..Next, there is the N-shaped SiC semiconductor by the cleaning of general method
The silicon carbide semiconductor device (step S2) in portion 1.
Next, (formation) is in N-shaped SiC semiconductor as shown in Fig. 2, the first electrode film 2 that will be made of nickel (Ni) forms a film
In portion 1 (surface) (step S3).Thin arrive of the thickness of first electrode film 2 can be using aftermentioned heat treatment and N-shaped SiC semiconductor portion
Silicon atom in 1 reacts and almost all is silicified (specifically, becoming nickel silicide (Ni2Si: hereinafter referred to as the first solid phase
State) film) degree, such as preferably 5nm or more and 10nm or less.Next, for example after the film forming of first electrode film 2 it
Afterwards, the second electrode film 3 being made of nickel silicide (NiSi: hereinafter referred to as second solid phase state) is formed on first electrode film 2
(step S4).It is formed as a result, and stacks gradually surface electrode film 4 made of first electrode film 2, second electrode film 3.In step S4
In, it is preferably formed as with the nickel silicide (Ni with the first solid state shape2Si) the second electrode film 3 of the composition of same degree,
In, the nickel silicide (Ni of first solid state shape2It Si is) by being heat-treated the silicon atom made in nickle atom and SiC semiconductor
It reacts and generates.That is, composition same degree of the composition of second electrode film 3 preferably with the first electrode film 2 after heat treatment.The
The thickness of two electrode films 3 is preferably, for example, 80nm or more.
In addition, in step S3, S4, first electrode film 2, second electrode film 3 film forming for example can be used direct current (DC:
Direct Current) sputtering method.Specifically, for example, SiC semiconductor matrix to the treatment furnace for being inserted into sputtering equipment
(part that the entire SiC semiconductor by including N-shaped SiC semiconductor portion 1 of silicon carbide semiconductor device is constituted) applies 300W's
Direct current power, under room temperature (such as 25 DEG C), that is, SiC semiconductor matrix is not heated, and at the argon of pressure 1Pa (Ar)
It is sputtered in atmosphere.The raw metal of sputtering target for first electrode film 2 to form a film for example can be purity 99.99wt%
Nickel.The raw metal of sputtering target for second electrode film 3 to form a film for example can be with 60Ni40Si (nickle atom
The containing ratio of 60atm% and silicon atom 40atm%) and 70Ni30Si (nickle atom 70atm% and silicon atom 30atm%'s contains
Rate) between range composition metal.
Next, to the SiC semiconductor matrix for the state for being laminated with first electrode film 2, second electrode film 3 (element is whole)
(step S5) is heat-treated in the vacuum atmosphere of high temperature.Specifically, in step s 5, for example, being vented to 5 × 10- 4With the high-temperature heat treatment of 1000 DEG C or so of temperature progress 5 minutes or so in Pa vacuum atmosphere below, it is cooled to room later
Temperature.By the heat treatment, the silicon atom in the nickle atom and N-shaped SiC semiconductor portion 1 in first electrode film 2 is reacted, generates nickel
The heating reactant for the electric conductivity that atom and silicon atom are mixed with scheduled atomic ratio.Specifically, 2 quilt of first electrode film
Silication generates the nickel silicide (Ni of the first solid state shape2Si).At this point, the whole almost all of first electrode film 2 is silicified, the
One electrode film 2 becomes the nickel silicide (Ni of the first solid state shape2Si) film.In addition, as noted previously, as heat treatment before second
Electrode film 3 is made of the nickel silicide (NiSi) of second solid phase state (or with identical as the first electrode film 2 after heat treatment
The composition of degree), therefore the surface electrode film 4 (first electrode film 2, second electrode film 3) after heat treatment is almost whole as nickel
Silicide film.
In addition, since the thickness of first electrode film 2 is thin, so because of first electrode film 2 and N-shaped in the heat treatment of step S5
The reaction in SiC semiconductor portion 1 and remaining carbon (C) atom is micro.In addition, because of first electrode film 2 and N-shaped SiC semiconductor
The reaction in portion 1 and the extra carbon atom generated is directed to second electrode film 3.Second electrode film 3 is due to being the gold comprising silicon
Belong to film, so not reacting with the silicon atom in N-shaped SiC semiconductor portion 1.That is, stacking first electrode film 2, second electrode film 3 and
At surface electrode film 4 in, only first electrode film 2 reacts with N-shaped SiC semiconductor portion 1 and generates extra carbon atom, this is extra
Carbon atom do not diffuse into the outside of surface electrode film 4.That is, be able to suppress surface from carbon atom to second electrode film 3 (with it is aftermentioned
Wiring layer interface) be precipitated.Next, formation (is not schemed by the wiring layer that aluminium (Al) is constituted for example on second electrode film 3
Show) (step S6).Later, by the common process implement after forming wiring layer, so that completion has and N-shaped
SiC semiconductor portion 1 forms the silicon carbide semiconductor device of the surface electrode film 4 of Ohmic contact.
Next, being verified to carbon atom from the amount of precipitation of surface electrode film 4.Fig. 3 is the surface indicated in previous example 1
The performance plot of the Elemental redistribution of the depth direction of electrode film.Fig. 4 is thickness (the Ni film for indicating the first electrode film in embodiment 1
It is thick) and the first electrode film after being heat-treated surface composition chart.Fig. 5 is the thickness for indicating the second electrode film in embodiment 2
Spend the chart of the surface composition of (NiSi film thickness) and second electrode film.Fig. 6 is the depth for indicating the surface electrode film in embodiment 2
The performance plot of direction elemental analysis.Fig. 3,6 Elemental redistribution and Fig. 4,5 surface composition be by using x-ray photoelectron
Optical spectroscopy (XPS:X-ray Photoelectron Spectroscopy), and alternately detect and sputter and measure surface electricity
The composition of the depth direction of pole film.
Firstly, being formed and N-shaped SiC semiconductor portion by the manufacturing method of previous general manufacturing silicon carbide semiconductor device
Form the surface electrode film (hereinafter referred to as previous example 1) of Ohmic contact.Specifically, in previous example 1, in N-shaped SiC semiconductor
It is formed in portion after the nickel film of the thickness of 100nm, being formed makes surface electrode film made of nickel film silication using heat treatment.Previous example
1 heat treatment condition is identical as aftermentioned embodiment 1.Then, it using XPS method, measures from the surface relative to surface electrode film
The Elemental redistribution for the depth direction that (surface (hereinafter referred to as most surface) with N-shaped SiC semiconductor portion side opposite side) is started.It will
The results are shown in Fig. 3.Result according to Fig.3, can confirm, in previous example 1, N-shaped SiC semiconductor portion (than nickle atom=
The part (the long part of sputtering time: the right part of Fig. 3) of 0atm% depth) in silicon atom and carbon atom be diffused into surface electricity
In the film of pole, carbon atom is largely analysed in the most surface (part (left part of Fig. 3) of sputtering time=0 minute) of surface electrode film
Out.
It is known that, conventionally, nickel reacts and is formed the nickel silicide (Ni of the first solid state shape with SiC semiconductor2Si).According to Fig. 3
Shown in result have confirmed that in previous example 1, the silicon atom and table being diffused into from N-shaped SiC semiconductor portion in surface electrode film
Nickle atom reaction in the electrode film of face, forms the nickel silicide (Ni of the first solid state shape2Si).In addition, having confirmed that from N-shaped SiC
The carbon atom being diffused into surface electrode film in semiconductor portion is precipitated in the most surface of surface electrode film.Surface electrode film most
The adaptation of carbon-coating and aluminium film that surface is precipitated is poor.Therefore, it is formed in this state in the most surface of surface electrode film by aluminium structure
At wiring layer in the case where, wiring layer is easily peeled off.It is found that needing to make N-shaped SiC to improve the adaptation with wiring layer
Carbon atom in semiconductor portion does not diffuse into the most surface of surface electrode film, or removes because of surface electrode film and N-shaped SiC semiconductor
The reaction in portion and remaining carbon atom.
Next, the condition of the diffusion as the carbon atom being able to suppress in N-shaped SiC semiconductor portion, to first electrode film 2
Thickness studied.Firstly, production is formed according to the manufacturing method of the manufacturing silicon carbide semiconductor device of above-mentioned embodiment
Become multiple samples (hereinafter referred to as embodiment 1) of the surface electrode film 4 of Ohmic contact with N-shaped SiC semiconductor portion 1.Specifically
For, in embodiment 1, first be made of nickel is formed in different thickness in N-shaped SiC semiconductor portion 1 by each sample
Electrode film 2 forms the of the thickness of 80nm being made of the nickel silicide (NiSi) of second solid phase state on first electrode film 2
After two electrode films 3, illustration it is above-mentioned each under the conditions of be heat-treated.As the sputtering target for being used to form first electrode film 2
Raw metal, use the nickel of purity 99.99wt%.As the raw metal for the sputtering target for being used to form second electrode film 3, make
With 67Ni33Si (metal comprising nickel 67atm% and silicon 33atm%).Then, it using XPS method, measures from by first electrode film
2, the element for the depth direction that the most surface (surface of second electrode film 3) for the surface electrode film 4 that second electrode film 3 is constituted is started
Distribution.It the results are shown in Fig. 4.The carbon composition (C composition) of Fig. 4 is amount of precipitation (figure of the carbon atom to the surface of second electrode film 3
5 is also identical).
Result according to Fig.4, is it is found that the thickness of first electrode film 2 is thicker, on the surface of first electrode film 2 (first
The interface of electrode film 2 and second electrode film 3) be precipitated carbon atom it is more.The reason for this is that nickle atom and n in first electrode film 2
The reaction quantitative change of silicon atom in type SiC semiconductor portion 1 is more, and extra carbon atom is easy to be discharged.Therefore, first electrode film 2
Thickness is preferably thin, but in the case where keeping the thickness of first electrode film 2 excessively thin (for example, 5nm or less left and right), due to first
The reaction of nickle atom in electrode film 2 and the silicon atom in N-shaped SiC semiconductor portion 1 is very few, so can generate not to Ohm characteristic
Good influence.Therefore, the thickness of first electrode film 2 is preferably capable forming good Ohmic contact with N-shaped SiC semiconductor portion 1
5nm or more and 10nm degree below.
Next, the condition of the diffusion as the carbon atom being able to suppress in N-shaped SiC semiconductor portion, to second electrode film 3
Thickness studied.Firstly, production is formed according to the manufacturing method of the manufacturing silicon carbide semiconductor device of above-mentioned embodiment
Multiple samples (hereinafter referred to as embodiment 2) of the surface electrode film 4 of Ohmic contact are formed with N-shaped SiC semiconductor portion 1.Specifically
For, in example 2, the first electrode film 2 of the thickness for the 10nm being made of nickel is formed in N-shaped SiC semiconductor portion 1, is pressed
Each sample forms be made of the nickel silicide (NiSi) of second solid phase state in different thickness on first electrode film 2
It is heat-treated after two electrode films 3.Other than the first electrode film 2 of the manufacturing method of embodiment 2, the thickness of second electrode film 3
Condition it is same as Example 1.Then, it using XPS method, measures from the surface being made of first electrode film 2, second electrode film 3
The Elemental redistribution for the depth direction that the most surface (surface of second electrode film 3) of electrode film 4 is started.It the results are shown in Fig. 5, figure
6。
It has confirmed that as shown in Figure 6, in example 2, from the boundary in N-shaped SiC semiconductor portion 1 and surface electrode film 4, (nickel is former
The part son=0atm% (right part of Fig. 6)), towards the most surface (part of sputtering time=0 point of surface electrode film 4
(left part of Fig. 6)), the containing ratio of carbon atom is reduced.That is, being able to suppress carbon atom from N-shaped SiC semiconductor portion 1 to table
It is spread in face electrode film 4.When first electrode film 2 is with a thickness of 10nm, in surface (2 He of first electrode film of first electrode film 2
The interface of second electrode film 3) containing ratio of carbon atom that is precipitated is 14atm% (referring to Fig. 4).Thus, it can be known that if by second
Electrode film 3 is formed to keep the containing ratio 14atm% of the carbon atom in the most surface precipitation of surface electrode film 4 below
The thickness of 80nm or more is then able to suppress the carbon atom being diffused into surface electrode film 4 and is precipitated in the most surface of surface electrode film 4
(referring to Fig. 5).
Therefore, the adaptation of surface electrode film 4 and wiring layer is verified.Firstly, the sample being produced as follows, that is, exist
The SiC substrate (semiconductor wafer) of 20mm square forms 2 He of first electrode film of the thickness for the 10nm that successively forms a film using sputtering
Surface electrode film 4 made of the second electrode film 3 of the thickness of 80nm is simultaneously heat-treated (hereinafter referred to as embodiment 3).Embodiment 3
Manufacturing method it is same as Example 1.As a comparison, production forms nickel film (surface electrode film) with the thickness of 90nm and carries out heat
Treated sample (hereinafter referred to as previous example 2).Condition other than the thickness of the nickel film of the manufacturing method of previous example 2 and previous
Example 1 is identical.Then, for embodiment 3 and previous example 2, aluminium film (cloth is formed with 5 μm of thickness in the most surface of surface electrode film
Line layer), the adhesive tape of aluminium film is attached at by removing, whether observation aluminium film is removed.Its result has confirmed that, in previous example 2, aluminium film
Almost whole face is all removed.On the other hand it has confirmed that, in embodiment 3, aluminium film is not peeling-off.As described above it could be speculated that in reality
Apply in example 3, by make first electrode film 2 with a thickness of 10nm or less and make second electrode film 3 with a thickness of 80nm or more come shape
At surface electrode film 4, the carbon atom in the most surface precipitation of surface electrode film 4 can be reduced.
As described above, according to embodiment, by forming the first electrode film thin by thickness in N-shaped SiC semiconductor portion
The surface electrode film constituted with the second electrode film being made of nickel silicide, so as to make surface in heat treatment later
The region that silication has been carried out because reacting with the silicon atom in N-shaped SiC semiconductor portion of electrode film is only the first thin electricity of thickness
Pole film.That is, due to can make to have carried out silication with the silicon atom in N-shaped SiC semiconductor portion because reacting region less than in the past,
So compared with the past can reduce the extra carbon atom generated in heat treatment.In addition, can will be generated because of the heat treatment
Extra carbon atom imported into second electrode film, be able to suppress most surface (second electrode film of the carbon atom to surface electrode film
Surface) be precipitated.Thereby, it is possible to improve surface electrode film and surface electrode film most surface formed wiring layer it is closely sealed
Property, make wiring layer be not susceptible to remove.
In addition, according to embodiment, even if the region of surface electrode film being silicified is less than in the past, surface electrode film with
Also almost all becomes the nickel silicide of the first solid state shape for the part (first electrode film) of N-shaped SiC semiconductor portion contact
(Ni2Si), thus, it is possible to the adhesive force in surface electrode film and N-shaped SiC semiconductor portion is maintained degree as in the past.By
This, is able to suppress surface electrode film and removes from N-shaped SiC semiconductor portion.In addition, by making partly leading with N-shaped SiC for surface electrode film
The part almost all of body portion contact becomes the nickel silicide (Ni of the first solid state shape2It Si), being capable of degree as in the past
Ohmic contact is formed with N-shaped SiC semiconductor portion.Therefore, connecing between first electrode film and N-shaped SiC semiconductor portion can be reduced
Electric shock resistance.Therefore, it is capable of forming the surface electrode film for showing good Ohm characteristic, also, by inhibiting extra carbon original
Son is into film and most surface is precipitated and ensures the adaptation of surface electrode film and wiring layer.
More than, the present invention is not limited to above-mentioned embodiments, are able to carry out without departing from the spirit and scope of the invention
Various changes.
Industrial availability
As described above, the manufacturing method of manufacturing silicon carbide semiconductor device of the invention is to various industry instruments, automobile etc.
Used manufacturing silicon carbide semiconductor device is useful, is particularly suitable for having the table that Ohmic contact is formed with N-shaped SiC semiconductor portion
The manufacturing silicon carbide semiconductor device of face electrode film.
Claims (6)
1. a kind of manufacturing method of manufacturing silicon carbide semiconductor device, which is characterized in that form the manufacturing silicon carbide semiconductor portion of N-shaped and formed
Ohmic contact between the surface electrode film on the surface in the manufacturing silicon carbide semiconductor portion, the system of the manufacturing silicon carbide semiconductor device
The method of making includes:
First formation process is made of as surface electrode film formation nickel on the surface in the manufacturing silicon carbide semiconductor portion
First electrode film；
Second formation process is formed as the surface electrode film and is made of nickel silicide on the surface of the first electrode film
Second electrode film；And
Heat treatment procedure, by making the silicon atom in the manufacturing silicon carbide semiconductor portion and the nickel of the first electrode film using heat treatment
Atomic reaction and make the first electrode film silication, to be formed between the manufacturing silicon carbide semiconductor portion and the surface electrode film
Ohmic contact,
In first formation process, the first electrode film is formed as into scheduled thickness, so that the first carbon atom becomes
The containing ratio of the inside of the second electrode film, first carbon are not precipitated and can imported into the most surface of surface electrode film
Atom, when making the first electrode film silication, is dissociated simultaneously from the manufacturing silicon carbide semiconductor portion in the heat treatment procedure
It is diffused into the carbon atom of surface electrode film side,
The second electrode film is that the containing ratio of nickle atom is 60atm% and the containing ratio of silicon atom is 40atm% to nickle atom
Containing ratio be 70atm% and the containing ratio of silicon atom is the composition of the range between 30atm%.
2. the manufacturing method of manufacturing silicon carbide semiconductor device according to claim 1, which is characterized in that
In second formation process, formation is able to suppress imported into the second electrode film in the heat treatment procedure
The second electrode film for the thickness that internal first carbon atom is precipitated to the surface of the surface electrode film.
3. the manufacturing method of manufacturing silicon carbide semiconductor device according to claim 1, which is characterized in that
In second formation process, the second electrode film is formed to inhibit in the heat treatment procedure and institute
State the composition that manufacturing silicon carbide semiconductor portion reacts.
4. the manufacturing method of manufacturing silicon carbide semiconductor device according to claim 1, which is characterized in that
In second formation process, the second electrode film is formed as and has carried out silication in the heat treatment procedure
The first electrode film the equal composition of composition.
5. the manufacturing method of manufacturing silicon carbide semiconductor device according to claim 1, which is characterized in that
The first electrode film with a thickness of 5nm or more and 10nm or less.
6. the manufacturing method of manufacturing silicon carbide semiconductor device according to any one of claims 1 to 5, which is characterized in that
The second electrode film with a thickness of 80nm or more.
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| PCT/JP2015/066078 WO2016013305A1 (en) | 2014-07-24 | 2015-06-03 | Method for manufacturing silicon carbide semiconductor device |
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| CN111276395A (en) * | 2020-02-19 | 2020-06-12 | 华芯威半导体科技(北京)有限责任公司 | Method for manufacturing silicon carbide device raw material and silicon carbide device prepared by using raw material |
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